This invention relates to bumper arrangements for vehicles and, more particularly, to bumper arrangements for automobiles equipped with longitudinal structural members that are zonally deformable.
A bumper arrangement for a vehicle with longitudinal structural members is disclosed in German patent application (Offenlegungsschrift) No. 2,137,515, 63c, 43/25. In that arrangement the front of the longitudinal members are circumferentially corrugated. These corrugations are designed so that they will fold together during an impact that is approximately in the direction of the axis of the corrugations. Thus, the longitudinal members will be zonally deformable in the region of the corrugations. With this type of bumper system, control of the deformation of the corrugations and, hence, the energy dissipation during an impact is difficult becuase the cross-sectional dimensions of the longitudinal member are generally constant in the deformable, as well as the non-deformable, regions.
The series connection of several shock absorbing elements along a section of a longitudinal member is described in Offenlegungsschrift No. 2,227,885, 63c, 70. However, in the bumper system of that German patent application the shock absorbers are piston-cylinder elements. Likewise, Offenlegungsschrift No. 2,216,270, 63c, 70, discloses a vehicle with a plastically deformable zone at the front of its longitudinal member, preceded by a hydraulic shock absorber. This shock absorber carries a bumper bar and, therefore, the deformation of the plastic zone of the longitudinal member occurs only after the shock absorber preceding it has been fully pushed in by an impact. Naturally, a bumper arrangement that combines deformable elements with a hydraulic shock absorber is much more expensive and complicated than an arrangement of deformable elements along.